It is well known that smoking marijuana leads individuals to experience something called ‘the munchies,’ where users tend to eat a lot more than normal. While you would think that this affect would lead marijuana-smokers to be more obese than non-smokers, there are now multiple studies which suggest that moderate use of marijuana can actually lessen the probability that someone will be obese (though it is possible that thinner individuals simply smoke more often than overweight individuals).

One such study that was published in the American Journal of Epidemiology, which found that marijuana use directly affects body weight, lowering rates of obesity by roughly a third among people who smoke pot at least three times a week compared with those who don’t use marijuana at all.

This study included over 52,000 participants, with cannabis users being obese less often than their non-using friends. Even after adjusting for other factors like age, body type, and habits like cigarette smoking, cannabis still caused a positive affect in body weight.

This could possibly be because many people who use cannabis regularly actually do so to instigate an appetite where one is lacking – such as in AIDS or cancer patients – and these individuals are less likely to be obese to begin with. But then the French study found:

“The adjusted prevalences of obesity in the NESARC and the NCS-R were 22.0% and 25.3%, respectively, among participants reporting no use of cannabis in the past 12 months and 14.3% and 17.2%, respectively, among participants reporting the use of cannabis at least 3 days per week. These differences were not accounted for by tobacco smoking status. Additionally, after adjustment for sex and age, the use of cannabis was associated with body mass index differences in both samples. The authors conclude that the prevalence of obesity is lower in cannabis users than in nonusers.”

In addition to this study are recent findings from GW Pharmaceuticals and the University of Buckingham which suggest that some of the compounds found in marijuana can have a beneficial effect for people suffering from metabolic diseases associated with obesity.

You can bet that the research is going to support the pharmaceutical versions of marijuana instead of the natural compounds:

Then there is the possibility that marijuana compounds lessen stress for individauls, which is a big motivator for many who over-eat or binge-eat due to anxiety and depression. The proof keeps stacking up – marijuana needs to be removed from Schedule I so more people can benefit from its medicinal qualities.

While smoking decreases, experts predict obesity will continue to increase

Obesity is set to overtake smoking as the most common risk factor for heart disease in Canada next year, a new study suggests.

Heart disease is a leading cause of death in this country, killing more than 70,000 people a year.

The study in Tuesday’s issue of CMAJ Open used a new model to estimate cardiovascular risk based on the lives of 22.5 million simulated Canadians aged 20 years and older.

Is obesity more of a marker of problems in broader society than a risk factor? (Howie McCormick/Associated Press)

“The most interesting finding for us is this idea that obesity looks like it’s going to continue to increase and smoking looks like it’s going to continue to decrease. That’s going to play out in heart disease,” lead author Dr. Doug Manuel, a senior scientist at the Ottawa Hospital Research Institute, said in an interview.

“When we first plotted out the numbers, we saw this big X where smoking crosses over obesity and obesity becomes the most common cardiovascular risk factor.”

“Obesity is no longer just a rich country’s problem. It’s now taken hold in poor and emerging countries and is rapidly developing into an insurmountable health crisis. Type 2 diabetes, heart disease and some cancers are on the march in nation’s ill equipped to treat sufferers or educate others about the dangers of getting too fat. It’s predicted that by 2030 one billion people will be obese, so how will the world cope with its ever expanding waistline?”

Obesity puts you at a greater risk of a variety of diseases—including breast cancer. But a recent study says the link between your waistline and breast cancer doesn’t stop there. Researchers with the Tulane School of Medicine say that obesity is directly related to breast cancer cell growth and even tumor size.

According to the study published in Breast Cancer Research, analysis of fat stem cell lines taken from women undergoing liposuction were injected into the mammary glands of mice where they accompanied breast cancer cells. The cells taken from obese women were associated with increased cancer cell numbers and tumor growth. Also significant, those cells taken from abdominal fat offered the most dramatic cellular changes.

The study concludes:

“ASCs isolated from the abdomen of obese subjects demonstrated increased expression of leptin, through estrogen stimulation, which increased breast cancer cell proliferation. The results from this study demonstrate that abdominal obesity induces significant changes in the biological properties of ASCs and that these alterations enhance ER+/PR+ breast cancer tumorigenesis through estrogen dependent pathways.”

The scientists believe the results could be due to the fat cells exposure to estrogen, which increases the production of the hormone leptin. Leptin, in turn, increases the number of cancer cells and the growth of tumors.

“It was determined that obesity alters the stromal cells (connective tissue cells of organs) and increases their expression of leptin,” explained lead author Bruce A. Bunnell. “Functionally, the altered stromal cells affect proliferation through several key molecular factors. Together this would suggest that obesity alters stromal cell function, which in turn alters breast cancer cells to increase their growth and progression.”

This isn’t the first study to link obesity and breast cancer risk – far from it. One published in JAMA over 7 years ago found 80,000 nurses who gained 55 pounds or more after the age of 18 had a 50% increased risk of breast cancer.

“While previous epidemiological studies have shown a link, we are one of the first to show the effects of altered stromal cells on the gene signature of breast cancers cells,” said Bunnell. “Furthermore, by identifying the differences between the stromal cells from obese women and lean women, we may be able to discover novel targets for therapeutic intervention.”

We know a lot about the causes of breast cancer, or at least what increases breast cancer risk. Our first line of defense against the disease, therefore, should be in applying these studies to our everyday life. If obesity increases breast cancer risk as well as tumor size and growth, it would stand to reason that avoiding obesity or losing weight if one is already obese could lessen your risk.

President Enrique Peña Nieto calls for a ‘change of culture’, including incorporating at least an hour of exercise for all Mexicans every day. Photograph: Marco Ugarte/AP

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Mexico has become the standard bearer in the global fight against obesity, after parliamentarians passed a law imposing significant new taxes on junk food and sugary drinks.

The vote by congress is a triumph for the anti-obesity crusade of President Enrique Peña Nieto, who will now sign the measures into law. As the legislation was passed, he called for a “change of culture” in his country, including the incorporation of at least an hour of exercise for all Mexicans every day. Mexico has higher rates of adult obesity even than the United States, according to the UN Food and Agricultural Organisation this year – 32.8% against 31.8% of Americans.

“We can’t keep our arms crossed in front of a real overweight and obesity epidemic,” the president said. “The lives of millions of Mexicans are literally at risk.”

Taxes on unhealthy foods and sugary drinks such as colas and lemonades have been introduced by a few other countries in Europe and Scandinavia, but often subtly. Mexico has confronted the food and drink industry head on, resisting tough lobbying and warnings that raising prices would do nothing to help the country’s economy.

But the government has taken the long view – that the potential economic harm from reduced junk food and soft drink sales now is insignificant compared with the damage in 10 years time if obesity continues at the current rate. The healthcare burden of diabetes and heart disease in Mexico is already huge and increasing. Some 9.2% of children in Mexico now have diabetes.

The taxes will increase the price of junk foods – those high in saturated fat, sugar and salt – by 8%. It will also put one peso (about 4p) on a litre of sugary drinks such as Coca Cola, which Mexicans consume in vast quantities at a rate of 43 gallons per person per year – the highest in the world. The money raised is intended to go towards health programmes and increased access to drinking water in schools. Among other measures, the government will introduce a nutritional stamp of approval for healthier foods on sale in supermarkets.

Obesity campaigners worldwide have been looking to food and drink taxes as a way to encourage people to change their diet and reduce the amount of fattening food and drink they consume. Norway has had higher duties on sugar, chocolate and sweetened drinks since 1981 and Samoa, which has very high obesity, has had taxes on sugary drinks since 1984. Australia introduced a 10% tax on soft drinks, confectionery, biscuits and bakery products in 2000.

Most of these taxes have not been high profile, however, avoiding a fight with industry. France attempted to introduce a tax on sugary drinks, but under pressure from manufacturers, conceded that it should apply to diet drinks as well as those containing sugar, which avoided characterising sugary drinks as unhealthy. Hungary has the most extensive anti-obesity tax, which applies to foods high in sugar, fat and salt as well as to sugary drinks, but it is at a low level and has also been politically difficult.

The food industry claims such taxes are a burden on the poor and do not work. They cite the Danish example. In 2011, the Danish government imposed a tax on all foods containing more than 2.3% saturated fat, which hit such popular staples as butter and bacon. It was unpopular partly because it was introduced by the treasury as a fundraiser, rather than being presented as a measure to improve population health.

Newspapers ran stories about Danes stockpiling and crossing the border to buy cheaper butter. Eventually the government fell, and the tax was withdrawn after six months.

But, says Professor Mike Rayner, director of the British Heart Foundation Health Promotion Research Group at Oxford University, “the Danish saturated fat tax is a dream from a researcher’s point of view. We’re beginning to get the preliminary results of the introduction of the tax. Of the data they have already got, it had a 4% effect on saturated fat levels. It is completely wrong to say it didn’t work.”

What is happening in Mexico is “really interesting”, he said. “We need more of these steps around the world to come up with good clear evidence of their effectiveness.”

Rayner and colleagues published a paper this week in the British Medical Journal based on modelling rather than real-life experience, which suggested a tax on sugary drinks of 20% in the UK would cut the number of obese adults by 180,000 and those who are overweight by 285,000.

Obesity drives an alteration of the gut microbiome, leading to the secretion of metabolites associated with the development of liver cancer.

By Chris Palmer | June 26, 2013

Fatty deposits (white) are scattered throughout this micrograph of a liver afflicted with non-alcoholic fatty liver disease.WIKIMEDIA, NEPHRON

Obesity spurs changes in the gut microbiome that can lead to the production of DNA-damaging metabolites. And according to new research published today (June 26) in Nature, circulation of these metabolites through the gut and liver initiate inflammatory and tumor-promoting factors that make mice more susceptible to liver cancer.

“This is a fascinating set of findings,” said Peter Turnbaugh, a systems biologist at Harvard University, who did not participate in the research. “This study shows that changes to the trillions of microbes that are found in the gut in response to obesity can contribute to the formation of damaging microbial metabolites.”

Obesity has been on the rise in developed nations over the past few decades, with one third of adults in the United States considered obese. Though obesity has long been linked to diabetes and cardiovascular disease, it is also increasingly being recognized as a leading risk factor in many forms of cancer.